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[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Nanotechnology is emerging in recent years and has attracted much attention from the food industry due to its great potential for wide applications in food safety and quality. The growing trend to use novel nanomaterials will revolutionize the food industry. On the other hand, the contamination of toxic nanomaterials in agricultural and food products has raised much concerned in consumers. The objectives of this study were to (i) establish novel methodologies to detect, characterize, and quantify the contamination of engineered nanoparticles (NPs) including zinc oxide, titanium dioxide, cerium oxide, and silicon dioxide NPs in various food samples (corn starch, yam starch, wheat flour, and soybeans, respectively); (ii) develop novel surface enhanced Raman spectroscopy (SERS) in combination with nanosubstrates for food safety applications. SERS was used to detect various chemical contaminants in drinking water. Our results demonstrate that the presence of NPs in foods can be detected and measured by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and transmission electron microscopy. The concentrations of NPs in food samples were measured by inductively coupled plasma optical emission spectrometry and epithermal neutron activation analysis. These results could help establish a systematic methodology for detection, characterization, and quantification of NPs in complex food matrices. In addition, SERS coupled with commercial gold nanosubstrates was used to detect chemical contaminants (atrazine, arsenic trioxide, bisphenol A, and bisphenol S) in drinking water. Satisfactory recoveries were calculated for atrazine and arsenic trioxide; while saturation of Raman signals at high concentration was observed for bisphenol compounds. These results demonstrate that SERS is a rapid, sensitive, and accurate method and has a great potential in applications in food and water safety.